Conventionally, there is proposed various applications for making/receiving calls among communication devices connected with each other via a network, as the network technology is advanced.
Further, digital devices become more and more sophisticated as the performance of processors is improved and the software technology is developed. Accordingly, various functions are begun to be installed in digital television display devices. As a result, the digital television display devices have become capable of, for example, obtaining television program information from a communication device connected via a network.
For the digital television display devices, there is proposed an Internet protocol (IP) phone function for making calls to or receiving calls from a communication device connected thereto via a network.
The digital television display devices receives terrestrial colorcast complying with the National Television System Committee (NTSC) standard, the Phase Alternation by Line (PAL) standard, or the like. The NTSC standard is used in for example Japan or America, and has the frame rate of 30 frames per second (fps). The PAL standard is used in for example China or European countries such as Germany, England, and Netherlands, and has the frame rate of 25 fps.
Conventionally, the broadcast waves of different frame rates, such as that of the NTSC standard and the PAL standard, could all be reproduced in a same device, thereby causing various negative impact. Therefore, the reproduction of the contents is made disabled if the frame rate (in fps) of the received broadcast waves deviates from a specified frame rate.
On the other hand, as far as the IP phone function is concerned, there should not be restriction on the frame rate because a frame rate for the IP phone function is made selectable from a certain range (e.g., from 5 fps, 10 fps, 15 fps, 20 fps, 25 fps, and 30 fps) according to the machine performance.